It sucks when that happens, especially when it's discovered after the fact and all involved have time/money invested in the steel.  Having worked in foundries/mills, manufacturing, and verification, I can attest first hand that loss of material traceability is rampant and even when the paperwork is in order mistakes still go uncaught.  Whatever your situation is, I would at the very least not assume it all as the same heat number.  Even knowing the method of manufacture for coil and that it's likely the entire coil is of the same heat, the MTR needs to match what was received in terms of specification, quantity, dimensions, etc. for QA/QC reasons.  Deviation from any of these metrics is cause to reject the shipment.  Call the mill or stockist and try and get clarification.  Sometimes there's a logical explanation.  If you're on the receiving end of a product made from the steel, and reviewing the accompanying documents, call it a nonconformance and put the onus on the manufacturer.

Hey Robert,

I often get tasked with Material ID on large shipments of structural steel that will have dozens or hundreds of pieces with the same Ht #.  On occasion a truck will have several different lengths of the same WF all with the same Ht#.  They are called out with separate MTR's or separate lines of the same MTR so an accurate accounting and traceability can be kept in tact.

Many of our items of differing grades and shapes will have a manufacturer's ID stenciled on them which makes it easy.  But more than once I have had to do some major digging to verify items. 

I would be willing to GUESS that somewhere there is another MTR with the balance of your material.  Someone just thought it was a duplicate and tossed it not realizing that they were for different parts of the order.  It can generally be found without too much effort.  Sometimes it is because they end up coming from different suppliers or at least different branches of the same supplier but the same manufacturer supplied them in the first place.

I would not recommend ignoring it.  In Tension, forgot his name, gave good advice.  It all depends on what the stage of the job is and if you have to do it or can throw the ball into someone else's court.

He Is In Control, Have a Great Day,  Brent